Zinc distillation plant



Jufiy 31, 1934.

w. MALKOMES ZINC DISTILLATION PLANT Filed June 13, 1931 E hi RT 3 i R z i QM QT 3 wk WW- Q m R? an A ww I MN N N m ln @N l sw 1 i Y Q wm m mm 1 b m wm N T and similar materials patented Juiy 31, 1934 ED STA TES' PATENT OFFICE mesne assignments, to

of Delaware, Pittsburgh, Pa.,

Delaware Application June 13,

In Germany May dust not completely separated out of the gases 6 Claims.

The invention-relates to a process and for the recovery of zinc from zinc oxide, ores containing zinc oxide or similar material in which briquettes are first made from the zinc oxide containing material and coal, and are then hardened by coking of the coal and finally are brought, pref-. erably in a continuous vertical retort oven, to the temperature required for the reduction of the zinc oxide and for the distillation of the metallic zinc.

In case of the well-known similar processes and apparatus, the coking of the zinc ore coal briquettes is efiected in retorts heated from the outside, in which cases the heating up of these retorts by the combustion of, producer gas or by similar means is carried out.

Now, the object of the present invention is a process for the recovery of zinc from zinc oxide in which first of all briquettes are made 'out of zinc oxide and coal, and which, for the purpose of coking, are brought into direct contact with the distillation gases resulting from the reduction of the zinc oxide after said gases have been freed from zinc and have been raised to the necessary temperature required for the coking by previous partial combustion. According to this invention preferably, for this purpose, the gases serving to heat up the zinc oxide-coal-briquettes are passed, in countercurrent to the briquettes, supplied continually or intermittently, through the shaft furnace used for the coking of the briquettes. Furthermore, according to this invention, all the gases leaving the coking ovens, after having been freed from the dust, tarand hydro-chloric vapours, are utilized for the preferably indirect heating up of the retorts of the coking oven. According to this invention, the gases are, previous to their further combustion in the heating flues of the reduction oven, led through a washer filled with limestone and sprayed from above with water for the purpose of removing the hydrochloric vapours.

The process according to this invention above all offers the important advantage, that the apparatus for the coking of the zinc oxide-coal briquettes can be made considerably smaller and cheaper than shaft furnaces serving for the coking, which have been customary up to the present and which are heated from outside. Moreover, in the case of the process of this invention, the otherwise necessary producer gas employed for the heating of the coking oven is dispensed with.

An additional advantage of the process accord- 65 mg to this invention lies in the fact that any zinc The Koppers Company a corporation of 1931, Serial No. 544,245

escaping the reduction oven in the usual zinc vapour condenser is, in consequence of passing of the gases through the coking shaft furnaces, precipitated during the'coking process on the surface of the zinc coal briquettes, which become plastic when heated so that the special removal of the zinc dust (necessary up to the present) from the waste gases of the reduction can be done away with.

On the drawing there is shown a vertical section of the apparatus serving to carry out the process in accordance with the invention.

In theapparatus shown on the drawing, a shaft furnace 1 is made use of for coking the zinc ore coal briquettes made in a briquette plate not indicated, said furnace 1 being provided above with a charging hole 4 which can be closed by means of the cover 3 movable to and fro by the hand lever 2. The lower discharging opening 5 of the coking shaft furnace is closed by the slide 6, which can be manipulated by means of a lever 7. Underneath the coking shaft 1 there is the heating chamber 8 of the reduction oven, the charging shaft 9 of which is connected up with the slide 6 and same can be closed by means of the slide. The heating chamber 8 is provided with the usual discharging appliance 10 with a run-01f hopper 11, which delivers the material freed from the zinc and drawn off continuously from the reduction oven to the lorries 12.

The heating of thereduction chamber 8 is effected extraneously by the gases, which are burnt in the customary heating flues 13 provided for in the walls of the reduction chamber 8. The heating flues 13 are each connected with crosschannels 14 and 15, which serve in alternation to supply the air for the combustion and to exhaust combustion products and the heating flues 13 are also in connection with channels 16 and 17 which supply the fuel gas for combustion.

The air supply channels 14 and 15 are connected up to the upper end of the regenerators 18, 19, respectively, which'are arranged above one another along one side of the battery of reduction chambers 8 and heating fiues 13. The regenerators are as usual fitted with refractory bricks forming chequer work and underneath each is provided with a bottom channel 21, 22. Each of the regenerators 18 are in connection with the usual regenerator box 25 by pipe lines 23, and each of the regenerators 19 are in connection with a similar regenerator box 25' by the pipe lines 24; and each of the boxes 25, 25', are connected by pipe line 26 with a waste gas due 2*? that leads to a stack as is usual with regenerators.

As is customary the regenerator bores 25, 25" are each provided with an air door 28 which are opened at times and allow entry of air into the pipes 23, 24, and thence to the regenerators l8, 19. Further, a valve is provided in each regeneratcr box for controlling the flow of waste gas there through to the pipes 26. When the air door 28 for a regenerator box is open the waste valve is closed, and. when waste valve is open the air valve 28 is closed, he air and i valves for the regenerators lb operate in alternation with the similar valves for the regenerators 19.

The horizontal connection channels 16 and N, that supply the fuel gasto the fines is con nected up by means or a three-way cool; 29 with a gas supply line 31.

The combustion of the fuel gas in the heating fiues 18 of the reduction chamber 8 is eiiected upwardly and then downwardly in alternation in the flues 13. For this purpose the three=way cool: 29 and the valves the boxes 25, 25, are periodi ically reversed (about every thirty minutes) so that in one thirty-minute period air and combos tible gas are fed into the lower ends or the heating fiues l3 and in the next thirty minute period air and combustible gas are fed into the upper ends of the fines 13. During such upilow cornbustion, the air valve 28 is open and the waste gas valve is closed for the regenerator boxes 25 of regenerators i9, and the waste gases pass from the horizontal fiues it into the regenerators it thence to their respective regenerator boxes 25' and out through the pipes 26, the waste gas valve being open and the air valve 28 for the boxes 25 being closed. Upon reversal the air valve is open and the waste gas valve is closed for the boxes 25'. Air then flows in through regenera tors l8 thence into the horizontal dues l4, meet= ing fuel gas, from the conduit l, in top of the vertical fiues it, burns downwardly therein, and the waste gas rowses out through the hori= zontal flues 5 to the regenerators it their re spective boxes 25 and thence to pipes 2d, the air valves 28 being closed and waste gas valves being open for the boxes 25.,

Tire gases and vapours containing zinc which escape on the heating up oi the carbonized zinc ore-coal briquettes are drawn oil at the upper end of the reduction chamber 3 by channel 32 leading out or the reduction chamber 8 and car ried off to a condenser 33 in which the zinc va= pours separate out in the form of liquid zinc metal, which can be drawn on by the opening 34 of the condenser. 33 continuously or intermit tently into a lor 35 run in front of the con denser 33.

The vapours and gases which are not precipi= tated in the condenser go forward through the pipe line 36 into a combustion chamber 3?, they are mixed with a certain quantity or air supplied by the pipe line so that a or the burnable gases entering the combustion chant ber 37 is burnt, thereby heating up the total quantity of gas. lhe gases heated up in combustion chamber at conducted through the pipe line 38 to the coldng shaft rur nace 1. They stream through charge in the coking shaft 1 in couctercturent to movement of same and are led from the coking shait through the pipe line to precipita means to which is provided with hotburrit v termediary floors 4i neoaois carried along with the gases. From the contrivance to the gases arrive then through the pipe lid to a recuperator 42 in which the hot gases serve to heat up the walls on the other side of which air is led for the purpose of being warmed up which then goes forward through the pipe line so to the. preliminary combustion contrivance 3'7. ihe gas spaces of the recuperator 42 are connected by means of the pipe line 43 with the washing tower a l which is packed with large grained limestone 45 and which is sprayed with water the top by means of the distributing contrivance d6. The washing water is drawn ofi through the pipe line 47 at the foot of the washer or and returned to the distributing contrivance by the pump 48 whilst a portion oi the spent washing water is removed continuously or intermittently and replaced by clean wateia At the upper end of the washer 44, there is connected up the gas pipe line 31, which serves to supply the gases to the valve 29 for delivery to horizontal channels 16, 17 or" the reduction chamher.

The invention as hereinabove set forth is embodied in a particular form of construction, but be variously embodied within the scope of the claims hereinafter made.

I claim:

l. A process for the recovery of zinc from oxidized zinc ores and the like and coal comprising, heating up and coking briquettes of the aforesaid materials by bringing the same in direct contact with the hot reduction gases from the following reduction step and heating and coking said briquettes by the sensible heat of said re= duction gases while hot from the reduction step, and then separately subjecting said cohed briquettes to further extraneous combustion heating and thereby reducing the oxidized zinc compounds driving on zinc vapours from the briquettes,

2. A process for the recovery of zinc from onidized zinc ores and the like and coal, which comprises: heating up and coliing briquettes of the aforesaid material; separately heating by ere trarieous combustion of gas the so coked briqu ettes to a temperature at which the oxidized zinc compounds are reduced and the zinc vapours driven on from the briquettes; efieoting partial combustion of the reduction gases from said reduction step and thereby further heating the same; bringing the latter gases into direct contact with the briquettes to be heated and coked and effecting the aforesaid heating and coking step with the sensible heat from the reduction step and from said partial combustion; and sub== the briquettes from the aforesaid heating and coking step to the aforesaid reduction step.

A process for the recovery of zinc from onidized zinc ores and the like and coal, which corn= prises: heating up and coking briquettes oi the aforesaid material; separately heating by extran= eous combustion oi gas the so colred briquettes to a teinperatiue at which the oxidized zinc compounds are reduced and the zinc vapours driven off i briquettes; eiiecting partial com= bastion the reduction gases from said reduc= tion and thereby further heating the same; bringing latter gases into direct contact with the briquettes to heated and colred and effect the aforesaid and coking step with ble heat from the reduction step and from tial iustion; subjecting the briquand coking step l iill prises: heating up and coking briquettes of the .aforesaid materials;

to the aforesaid reduction; and preheating the air for said partial combustion step by heat exchange with the spent gas from said heating and coking step.

4; A process for the recovery of zinc from oxidized zinc ores and the like and coal, which comaforesaid material; separately heating by extraneous combustion of gas the so coked briquettes to a temperature at which the oxidized zinc compounds are reduced and zinc vapours driven off from the briquettes; bringing reduction gases from said reduction step while hot into direct contact with the briquettes to be heated and coked and heating and coking said briquettes by the sensible heat of said reduction gases while hot from the reduction step; passing spent reduction gases from said heating and coking step to said reduction step and effecting the heating of said reduction step by extraneous combustion of said spent gases.

5. A process for the recovery of zinc from oxidized zinc ores and the like and coal, which comprises: heating up and coking briquettes of the separately heating the so coked briquettes to a temperature at which the oxidized zinc compounds are reduced and zinc vapours driven off from'the briquettes; bringing reduction gases from said reduction step while hot into direct contact with the briquettes to be heated and coked and heating and coking said briquettes by the sensible heat of said reduction gases while hot from-the reduction step; passing spent heating gases from said heating and coking step to said reduction step and effecting the heating ofsaid-reduction step by extraneous combustion of said spent gases and air regeneratively preheated by waste heat of said combustion.

6,. A process for the recovery of zinc from oxidized zinc ores and the like and coal, which comprises: heating up and coking briquettes of the aforesaid material; separately heating the so coked briquettes to a temperature at which the oxidized zinc compounds vapours driven off from the briquettes; effecting partial combustion of the reduction gases from said reduction step and thereby further heating the same; bringing the latter gases into direct contact with the briquettes to be heated and coked and effecting the aforesaid heating and coking step with the sensible heat from the reduction step and from the partial combustion; preheating the air for the partial combustion by heat exchange with spent gases from the heating and coking step; cleaning the spent heating gases from said heating and coking step and thereby freeing them from dust, tar and hydrochloric acid; passing the so cleaned gases to said reduction step, and effecting the heating of the reduction step by extraneous combustion of said cleaned gases with air regeneratively preheated by the heat from the combustion products of said cleaned gases.

WALTER MALKOMES.

are reduced and zinc 

